Method and arrangement for X-ray photography or the like

ABSTRACT

For taking X-ray photographs there is provided a moveable tower structure for ceiling-mounted frame which carries a beam source arranged for movement in X-Y-Z directions and which is rotatable about a horizontal axis. A receptor unit is mounted beneath a patient support table for movement in the X direction and Y direction. Activation of a holder associated with the receptor unit and intended to receive a vertically extending secondary receptor for horizontal beam path causes the beam source to move automatically to a basic setting.

TECHNICAL FIELD

The present invention relates to a method for taking X-ray photographsor the like with the aid of a beam source which is carried for movementin X, Y and Z directions and which is rotatable about a horizontal axis,and also with the aid of a patient support table and a receptor unitwhich is positioned beneath the table and capable of being moved in theX and Y directions and which when displaced automatically instigatesmovement of the beam source.

By X-direction is meant here and in the following a direction ofmovement parallel with one long side of the patient support table, andby Y-direction is meant a direction of movement perpendicular to theextension of said one long side, i.e. movement parallel to the shortside of the table. The patient support table may therewith be adjustedto mutually different positions in relation, for instance, to a towercolumn or ceiling-support tower which carries the beam source. In allinstances the expression "X-direction" refers to movement parallel withthe long side of the table.

The invention also relates to X-ray photography apparatus.

BACKGROUND PRIOR ART

U.S. Pat. No. 4,365,345 (Craig et al) describes apparatus of this kind,in which, however, the beam source is located beneath the table in theactual patient investigation part of the apparatus, and the imagereceptor is located on a tower structure arranged above said patientinvestigation part. When the beam source is moved in the X- andY-directions these movements are transferred to the receptor over aservo system. In this case, the actual patient investigation part isexpansive and space consuming and is found difficult to work with by theX-ray personnel. Another significant drawback with this known apparatusis that there is no possibility of taking side photographs with ahorizontally directed beam path.

U.S. Pat. No. 4,024,403 (Bernstein et al) teaches a conventional towerstructure with manual adjustment of the patient support table, anoverlying beam source and a receptor located beneath the table. Theapparatus includes an electrical auxiliary device for adjusting the beamsource angle and synchronized movement of the receptor corresponding tosaid angular adjustment, such that the central beam will always impingeon the patient at the correct angle.

The work required from the X-ray personnel with this type of X-rayequipment is both laborious and complicated, placing great strain on theshoulders and back muscles of the personnel as a result of the manualadjustment movements which must be carried out, not least thedisplacement of the heavy beam source. This equipment also lacks afacility for taking side photographs with horizontal beam path.

U.S. Pat. No. 4,365,344 (Dornheim) provides an example of apparatusincorporating mechanical synchronization between the setting movementsof the receptor and beam source. This arrangement utilizes a complicatedlever system, which makes the work carried out by the X-ray personnelboth heavy and complicated, primarily because of the large masses whichneed to be activated, and also because of the stretching and bendingrequired of said personnel. Furthermore, the receptor part of theapparatus must be lifted up each time a side photograph is taken. Thepossibility of taking angled photographs is limited.

U.S. Pat. No. 3,492,482 (Forsyth) describes and illustrates a beamsource which is mounted on a vertical tower structure and which ismovable in the Z-direction, and a receptor part which is movedsynchronously with the beam source on a corresponding vertical towerstructure. The apparatus is intended exclusively for taking sidephotographs with horizontal beam path, and the apparatus consequentlyhas a limited field of use.

GB-B-1,323,769 (Picket Corp) describes apparatus comprising a receptorpart in a patient support table and an overlying ceiling-carried beamsource. This apparatus affords the possibility of taking sidephotographs with horizontal beam path, by swinging-up the patientsupport table about a horizontal axis and pivoting the beam source. Theapparatus also enables the image size and shutter setting to be variedin relation to the beam-source/receptor distance ("SID", i.e."source-image-distance"). Movement of the beam source and swinging ofthe patient support table, however, must be effected manually,circumstances which are also experienced as troublesome by the X-raypersonnel.

SE-B-7906060-5 (Philips) describes a similar arrangement of apparatus,although in this case the beam source is located in the pivotal patientsupport table and the image receptor is located on a ceiling-carriedframe structure, even though it is stated in the descriptive part of thespecification that the arrangement may be reversed. Movements of thereceptor and beam source in the X-direction are synchronized. Whenswinging up the table incorporating the beam source, the receptor isrotated around the horizontal axis synchronously therewith. It is alsostated that the receptor and beam source can also moved synchronously inthe Y-direction, although this is not illustrated in the specification.

This arrangement of apparatus also has the drawbacks associated with apivotal patient support table, inter alia because of the large masseswhich need to be set in motion when taking side photographs, and becauseof the limited use possibilities of the apparatus in general. Forexample, there is no facility for taking side photographs of a seatedpatient. In summary it can be said that all apparatus or equipment ofthis kind lack the requisite flexibility.

Other examples of known X-ray tower structures are described andillustrated in DE-A1-3,406,717 (Philips), DE-A1-2,831,058 (Philips) andU.S. Pat. No. 4,501,011 (Hauck et al).

THE OBJECTS OF THE INVENTION

One object of the present invention is to provide an X-ray photographymethod which will avoid the aforesaid drawbacks, and other drawbacks,associated with known methods and which will enable X-ray photographs tobe taken with vertical, horizontal and angled beam path with the aid ofsolely a single beam source without discomfort to the patient, i.e.without needing to manipulate the patient or the patient support tableto any appreciable extend when adjusting the positions of the variousX-ray devices, and without requiring heavy and laborious adjustment workto be carried out by the X-ray personnel. Neither shall the patienthimself/herself need to cooperate actively in the investigation.

A further object is to provide a method of the aforesaid kind which willfacilitate the work of the operator, particularly in those cases wheredifferent types of photographs are to be taken.

Still a further object of the invention is to provide a method of theaforesaid kind which offers increased flexibility, with the aid ofsimple means, i.e. so that the X-ray equipment enables photographs to betaken other than the "normal" photographs of a lying patient withvertical, horizontal or angled beam path, such as photographs of asitting or standing patient for example.

A particular object of the invention is to provide a method and a systemof apparatus which will enable a large number of mutually varying typesof photographs to be taken without imposing difficulties on the X-raypersonnel or discomfort to the patient, or in other words a universalsystem of apparatus for use in conjunction with X-ray photography.

SUMMARY OF THE INVENTION

These and other objects are fulfilled by a method according to theinvention, which is mainly characterized in that activation of areceptor unit associated with a secondary receptor extending in thevertical plane results in, optionally after a time delay, automaticmovement of the beam source to a basic setting for horizontal, centeredbeam path onto the secondary receptor.

Correspondingly, activation of the primary receptor located beneath thepatient support table, optionally after a time delay, causes the beamsource to return to a basic setting for vertical beam path from theprimary receptor.

It is preferred in practice that the beam source in each basic settingposition is caused to take a pre-determined distance from respectivereceptors.

The invention affords the important advantage that X-ray personnel needonly manipulate the small mass exhibited by the receptor unit, which islocated at a comfortable working height beneath the patient supporttable, whereafter all setting movements of the heavy beam source areeffected through the agency of separate, servo-controlled drive units.

In certain cases the secondary receptor may be stationarily mounted onthe movable receptor unit. One requirement in this regard, however, isthat the secondary receptor will not cause an obstruction when thepatient is transferred to the table or when adjustments are to be madeto the position of the primary receptor.

Preferably, however, the secondary image receptor is mounted on a holderassociated with and movable together with the primary unit, prior toactivating the receptor.

To this end, the receptor unit may include, for instance, several typesof holder means into which the secondary receptor can be placed.Alternatively, the secondary receptor may be connected to the receptorunit by a pivotal holder means which will enable the secondary receptorto be dropped to a "parking position" when not in use. In this case, thereceptor is applied by being swung-up to its active position, prior toactivation of the secondary receptor.

When moving the beam source to either of its basic setting positions,the source is swung through 90° around the horizontal axis and alsomoves in the Z-direction. Normally, movement also takes place in the X-and/or Y-directions. The beam source auxiliary means receivesinformation relating to the type of secondary receptor used and thesubsequent activating operation will result in pre-determined movementof the relevant beam source drive means.

Normally, it is desirable to place the receptor as close as possible tothe patient, in order to obtain optimum image sharpness. In certaintypes of known X-ray equipment particular difficulties are experiencedin taking side photographs with horizontal beam path, since thisequipment has not been sufficiently prepared for such photographs.Consequently, in the case of some patients it is necessary to makeprovisional arrangement for holding the receptor, and in certaininstances it may be necessary for the patient himself to hold thereceptor.

Unsuitable arrangements such as these can be avoided when practicing thepresent invention, since the invention provides mutually differentsecondary receptors, from which the most suitable receptor for thepurpose in question can be selected in each particular case. Theapparatus is also able to detect the type of receptor used in eachparticular case, therewith enabling adjustments and/or collimation ofthe beam source to be carried out automatically when necessary.

It also lies within the scope of the invention to provide thepossibility of using a secondary receptor carried on telescopic arms, sothat the receptor can be brought into the close proximity of thepatient. In this case the beam source will obtain information relatingto the prevailing setting position of the receptor so that the beamsource is adjusted automatically to a position corresponding to thereceptor setting.

When photographing such parts of the body as the spine, kidneys andother organs with the patient in a recumbent position, the object willnormally be located close to the table top. In this case, with selectionof a suitable film or receptor format, the receptor should be locatedclose to the table top in order for the object to lie in the center. Inorder to maintain a constant SID, the necessary adjustment movements arefacilitated while ensuring, at the same time, optimum image quality.

For example, a secondary receptor holder can be placed on each side ofthe receptor unit, i.e. on each side of the patient support table. Inthe manner aforedescribed, the apparatus detects the location of thesecondary receptor and the position of the beam force is adjustedaccordingly.

Furthermore, the invention has the important advantage of affording thegreatest possible protection to the patient, which is, of course, ofparticular benefit when taking X-ray photographs of unconscious and/orseriously injured patients. When practicing the present invention, suchpatients need not be moved, irrespective of the type of X-rayphotographs to be taken.

Another important advantage afforded by the invention is that thepattern of movement carried out by the beam source can be programmed sothat none of the movable components or parts need be brought to aposition which is so close to the table as to cause injury to thepatient. Expressed in another way, it can be said that the movementpattern of the equipment components shall be programmed in a manner suchas to create a protective shell around a patient on the patient supporttable.

Particular advantages are also afforded when photographing with anangled beam path. In this case, the receptor unit will preferablyexhibit a grid comprising mutually parallel lamellae which extend in theX-direction. The setting of the beam source is automatically adjusted independence on the angle of inclination to which said beam source is set,so that the beam path will always be centered relative to the receptor.

This will greatly reduce, or even eliminate, the risk of taking blurredor completely erroneous photographs, and also the risk of subjecting thepatient unnecessarily to an excessively high dosage of X-ray because ofthe need to re-take photographs.

In this regard, it is possible, within the concept of the invention, forthe apparatus to indicate the type of grid used, e.g. with the aid of avisual display or some other manner, which in turn will correct SIDautomatically in relation to the collimated beam source. At the sametime, it is possible to make desired and suitable changes to the focusdistance, with the purpose of achieving desired yields of the exposuresmade. As a complement to the table receptor, with its possibility ofusing one or more secondary receptors, it also lies within the conceptof the invention to provide a tertiary receptor, for instance on a towerstructure forming part of the equipment apparatus, or a separate towerstructure, which may be a static fixture or movable. The most importantpurpose of a tower-carried receptor is that of enabling lung photographsto be taken, in which case the patient normally stands facing towardsand close to the receptor. In this case, it is suitable for the receptorholder to face laterally outwards from the tower structure.

A third basic setting position relating to a tertiary receptor can alsobe utilized for taking other normally occurring photographs, e.g. aloaded knee, hip etc. In this case, the tertiary receptor is lowered toa suitable height, the beam source automatically following the movementcarried out by said receptor.

The patient support table may be made longer than is normally the case,so as to provide at one end of the table a space in which a seat can beplaced so as to enable photographs to be taken with the patient in asitting position, e.g. sinus investigations, which are often carried outin conjunction with a lung X-ray. The seat unit is preferably capable ofmoving in the longitudinal direction of the table and is also preferablyrotatable. The primary receptor unit located beneath the patient tablecan also be used even when the seat unit is being used. In this case, afurther, specially designed holder for a secondary receptor can befitted, and the height of the holder adapted for taking photographs of aseated patient. When applying this holder, the aforesaid control meansreceives corresponding information and, optionally subsequent to theaforesaid activation of an auxiliary operating device, the beam sourceis automatically adjusted to its basic setting in relation to theapplied secondary receptor.

Movement of the tower structure and the beam source carried thereby inthe X, Y and Z directions is preferably effected with the aid ofelectric motors. The rotary movements carried out by the beam source arealso preferably effected with the aid of an electric motor connected tothe rotational axle of said source.

Manually effected setting movements of the receptor unit are transferredto the different motors for executing movement of the beam source, in asuitable known manner. In order to achieve the exactitude desired, thereare preferably used analogue or digital position sensors, e.g.multi-coil potentiometers or pulse emitters suitable for the purpose inquestion. The system may also include means for automatic movement ofthe receptor unit to given preprogrammed positions.

As before mentioned, the respective components are moved to their basicsettings automatically. Movement of said respective components fromtheir basic settings is preferably effected with the aid of suitablebuttons placed on a comfortably positioned operating panel, andindicating in a suitable manner, preferably digitally, deviations fromsaid respective basic setting positions.

The invention also relates to a system of apparatus for taking X-rayphotographs or the like, said system being substantially characterizedby the features set forth in the accompanying claim.

Further characteristic features of the inventive method and system willbe apparent from the following description of a number of exemplifyingembodiments of the invention, made with reference to the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates in perspective a system of apparatus for X-rayphotography in accordance with the invention, including a patientsupport table provided with an image receptor unit and a displaceabletower structure carrying a beam source.

FIG. 2 is a corresponding view in perspective, showing the beam sourcepositioned in a basic setting for vertical beam path.

FIG. 3 is a part view illustrating the beam source in position forangled beam path.

FIG. 4 illustrates the system subsequent to inserting a secondaryimage-receptor holder and with the beam source in its basic settingposition for horizontal beam path.

FIG. 5 illustrates the apparatus of the system set to a position fortaking X-ray photographs of the lungs in particular with the aid of atower-carried tertiary receptor holder and with the beam sourcepositioned in a basic setting for horizontal, centered beam path on saidreceptor.

FIG. 6 illustrates one end of the patient support table which hasmounted thereon a seat unit for taking X-ray photographs of a seatedpatient and having attached thereto a secondary receptor holder adaptedfor this purpose.

FIG. 7 illustrates the system of apparatus shown in FIG. 5 with the beamsource and the receptor holder in a position for taking a photograph,e.g., of a "loaded knee" of a patient.

FIG. 8 is a side view, partly cut away, of an arm which projects outfrom the tower structure and which carries a carriage for movement ofthe beam source.

FIG. 9 is a horizontal sectional view illustrating the arm of FIG. 8from above.

FIG. 10 is a horizontal sectional view corresponding to FIG. 9,subsequent to movement of the carriage and outward swinging of the beamsource.

FIG. 11 is a side view, partially cut away, of another part of the towerstructure shown in FIG. 1, and illustrates an arrangement for displacingthe arm and the tower-carried receptor holder linearly in theZ-direction.

FIG. 12 is a side view, partially cut away, of a lower part of the towerstructure shown in FIG. 1, and illustrates bottom guide means and drivemotor for horizontal movement of the tower structure.

FIG. 13 illustrates in perspective part of a patient support tableprovided with a receptor unit and two alternative secondary receptorholders capable of being mounted in the receptor unit, on either side ofthe table.

FIG. 14 is a perspective view of a universal receptor holder.

FIG. 15 is a side view of the holder shown in FIG. 14 and indicates thepresence of a receptor in said holder.

FIG. 16 is a perspective view of an alternative system of apparatus, inwhich the patient support table extends perpendicularly to a wallstructure and the X and Y axes have subsequently changed places. Thissystem of apparatus also includes a number of additional modificationsto previously illustrated embodiments.

FIG. 17 illustrates in perspective a system of apparatus according toFIG. 16 in an operative state.

FIG. 18 illustrates further a method of use of a system according toFIG. 16 and 17.

FIG. 19 is a perspective view which illustrates a further embodiment inthe form of a ceiling-mounted tower or column structure and a receptorunit provided with a fixed secondary receptor holder.

FIG. 20, finally, illustrates the principle of use of a system ofapparatus according to the invention for linear tomography.

DESCRIPTION OF PREFERRED EMBODIMENTS

FIG. 1 illustrates a system of apparatus for X-ray photography,comprising a raiseable and lowerable patient support table 1, which ispreferably firmly mounted on the floor, and a floor-mounted andceiling-mounted tower structure 2 carrying a beam or X-ray source. Thetower structure is capable of being moved in the X-direction along thetable 1 in a bottom floor-mounted guide means 3 and a topceiling-mounted guide means 4. The tower structure 2 has projectingoutwardly therefrom an arm 5 which can be moved upwards and downwards,i.e. in the X-direction.

The arm 5 carries a beam source 6 which is movable along said arm in theY-direction and which can be swung or pivoted about a horizontal axis.

Arranged beneath the patient support table is a receptor unit orreceptor holder 7 for accommodating a receptor 7a, said unit having theform of a carriage which can be moved linearly in the X- andY-directions. Extending from each side of the unit 7 is a carrier means7b for an operating handle 8. The unit can be caused to move in the Xand Y directions by gripping the handle 8 such that the image receptorwill obtain an accurately defined position in relation to the X-rayphotograph to be taken. The handle 8 also incorporates a recess 8a inwhich an alternative secondary receptor holder 15 (see FIG. 4) forhorizontal beam path can be mounted, as hereinafter described in moredetail.

The outwardly projecting arm 5 carries a downwardly extending part 5a onwhich there is mounted a laterally projecting further holder 9 intendedfor receiving a tertiary or third receptor, which accompanies movementof the arm in said X and X directions.

FIG. 2 shows the apparatus of FIG. 1 adjusted to a basic setting forvertical, centered beam path onto a receptor 7a located in the receptorunit 7. The receptor may be of varying construction, size and shape andthe receptor holder or "back surface" can be configured to center thereceptor automatically as it is placed in the holder, irrespective ofthe configuration, size and shape of the receptor.

FIG. 3 illustrates the beam source 6 adjusted to a position for angledbeam path, the tower structure 2 and the arm 5 having been moved in theX-direction from the position illustrated in FIG. 2 and the beam sourcehaving been rotated about a horizontal axis by a drive motor 10 throughan angle α, which normally lies between 0° and 20°, depending upon thephotographs to be taken. In accordance with the basic concept of theinvention as disclosed above, a setting of a given angle α on anoperating panel (not shown) results in movement of the tower structure 2and the arm f through a corresponding distance, so that the beam sourcesubsequent to rotation through said angle α about the horizontal axisemits X-rays in a manner to impinge upon a receptor located in thereceptor unit 7; prior to setting the angle by means of the operatingpanel, the operating system as a whole is preferably deactivated bymeans of a separate operating device 11 (see FIG. 1) connected to orlocated adjacent to the operating handle 8.

In this case, displacement of the receptor unit 7 in the X and Ydirections results in corresponding, programmed movement of the towerstructure 2 and the outwardly projecting arm in the X-direction, and bymovement of the arm 12 carrying the beam source 6 in the Y-direction.

FIG. 4 illustrates the events that take place when a secondary receptorholder 15 is mounted in holes 8a provided in the handle part 8 of thereceptor unit 7. Subsequent to activating an operating device on thepanel, positioning the secondary receptor holder in said holes resultsin downward movement of the arm 5 in the Z-direction, outward swingingof the angled arm 12, and rotation of the beam source through 90° aboutthe horizontal axis, to a basic setting horizontal, centered beam pathon a receptor located in the thus mounted receptor holder 15.Displacement of the handle in the X and Y directions, which results incorresponding displacement of both the receptor unit 7 and the receptorholder 15, also results in automatic displacement of the tower in theX-direction and displacement of the angled arm 12 in the Y-direction,along the arm 5, i.e. such that the beam source 6 is maintained in itsposition for horizontal, centered beam path onto the receptor in thereceptor holder 15.

FIG. 5 illustrates a basic setting in which the beam source 6 isadjusted for horizontal beam path onto a receptor in tertiary receptorholder 9 carried by the arm 5 via the downwardly extending part 5a. Thisposition is also reached automatically, upon receipt of a commandsignal.

This illustrated basic setting of the relevant components enables, forinstance, lung photographs to be taken, with the patient locatedcontiguous with the receptor in the holder and with his/her back facingthe beam source 6. Activation of means on the operating panel for thisparticular basic setting results in corresponding movements of the beamsource 6. It shall be observed that the receptor holder 9 and the beamsource 6 carry out, in this case, mechanical synchronized movements inthe X and Z directions. As will be understood, the beam source may beangled relative to the receptor unit.

FIG. 7 illustrates substantially the same basic settings as thoseillustrated in FIG. 5, although with the difference that the receptorholder 9 and the beam source 6 have been moved downwardly in theZ-direction. This positional setting can be utilized, for instance, whentaking photographs of a loaded knee, etc.

FIG. 6 illustrates a modification of the patient support table 1 shownin FIG. 1, the table of the FIG. 6 embodiment being lengthened so as toprovide room for a seat unit 18 which enables photographs to be taken ofpatients in a sitting position. The illustrated seat unit 18 is movablein the width direction of the table, and is also preferably rotatable.When the seat unit 18 is used, a secondary receptor holder 15',particularly constructed to this end, is fitted in to the holes 8a (SeeFIG. 1) of one of the handle parts 8. The receptor holder 15' has alonger holder part than the holder 15 illustrated in FIG. 4. Applicationof the receptor holder 15' results in corresponding information to theoperating system of the beam source, which in accordance with theaforegoing automatically adjusts the beam source to a basic setting forhorizontal, centered beam path onto a receptor located in the holder 15,subsequent to activation of an operating device. The beam source canthereafter be moved from this basic setting to any of a number ofdesired settings.

FIGS. 8-10 illustrate an exemplifying embodiment of a drive arrangementfor movement of the beam source 6 in relation to the arm 5.

The beam source 6 is carried by the angled arm 12, which is suspendedfrom a peg 20 in a carriage 21, which is mounted on the outwardlyprojecting arm 5 of the tower structure and runs on ball bearings 22 insaid arm. The carriage is driven by a motor 23 comprising a line pulley23a, having extending therearound a line 24 connected to the carriage.The peg 20 carries a toothed wheel 25 on the upper side of the carriage21. When the toothed wheel 25 passes a toothed segment 26 fixedlymounted on the arm 5, as the carriage 21 moves, the peg 20 is caused torotate and therewith swing the beam source 6 to the position illustratedin FIGS. 4-7.

FIGS. 11 and 12 illustrate an exemplary embodiment of a drivearrangement for effecting movement of the outwardly projecting arm 5 inthe Z-direction and for effecting movements of the tower structure inthe X-direction.

The tower structure 2 carries a bracket structure which extendsdownwardly into the guide 3 and which comprises two mutually parallelparts 30, 31, of which the part 31 supports a drive motor 32. The outputshaft of the drive motor supports between the bracket parts 30, 31 awheel 33 of V-shaped profile, which runs on a guide 34 of circularcross-sectional shape. A ball bearing 34 is journalled in the lower partof the tower 2 for movement on the upper side of the guide 3. Rotationof the motor 32 results in linear displacement of the tower structure inthe X-direction.

Also arranged at the bottom of the tower structure 2 is a drive motor 35which co-acts with a screw 38 having a trapezoidal screw thread, via agear arrangement 36, 37. The arm 5 and the downwardly projecting armpart 5a carrying the receptor holder 9 accommodate two journal parts 5bwhich embrace the screw 38 and exhibit corresponding trapezoidal threadsections. When the screw 38 is turned in either direction, the arm 5 andthe receptor holder 9 are displaced correspondingly in the Z-direction.

FIG. 13 illustrates the aforesaid handle parts 8 located on mutuallyopposite sides of the table 1 and connect to the receptor unit 7 locatedbeneath the table. The Figure also illustrates the capability of thehandle parts to accomodate receptor holders 15 and 15' respectivelywhich are intended for a horizontal beam path and which are of mutuallydifferent configuration. The connecting holes 8a in respective handleparts 8 are configured so that solely a given receptor holder can befitted into corresponding pairs of holes. In this way, the drive systemof the X-ray apparatus will receive information relating to the type ofreceptor holder mounted in the handle at that time, whereupon the beamsource is adjusted to a corresponding setting.

Consequently, it lies within the concept of the invention to utilize aplurality of different types of secondary receptor holders which can bemounted or applied alternatively. When such a secondary receptor holderis applied, the beam source will automatically carry out correspondingmovements, subsequent to activation of an operating device, such as toadopt a basic setting position for horizontal centered beam path ontothe receptor in the holder in question. The holder of the FIG. 13embodiment has a bracket part 15b provided with connecting pins 15c.

A pack of microswitches for enabling the movement combinations requiredfor the correct function of the system may be connected to the systemoperating panel.

As will be seen from FIG. 13, the operating device of the illustratedembodiment has the form of a "slave button" 11 which serves as a mainswitch for activating and deactivating the aforesaid operationalmovements. This operating device, however, may alternatively have theform of a "dead mans grip" which enables the receptor unit 7 to bedisplaced when the handle part 8a is gripped. As will be understood,when setting the receptor unit in position, the handle is gripped andthe setting movements required to move the beam source to its correctposition are carried out automatically.

In the case of the inventive system, respective receptor holders, 7, 9,15 are able to accommodate different types of receptor. For example, thereceptor holder may have the form of a box, into which a cassette isinserted. The box may include an additional slot, into which a grid isinserted. Thus, when taking side photographs, it is possible to select acassette which incorporates a grid, or a standard cassette with separategrids.

An inventive system can also accommodate all the various kinds of imagereceptor that can be used. In this regard, the actual receptor holdermay, in certain instances, have the form of a frame into which cassettesof various sizes can be inserted, optionally with built-in grids forease of exchange.

An exemplifying embodiment of an alternative universal receptor holderis illustrated in FIGS. 14 and 15.

The holder 40 is intended to replace a separate holder for differentimage formats with a universal holder which can be used for all presentday formats of, e.g., X-ray film cassettes or images plates.

The illustrated holder comprises two mutually angled rails 41, 42 whichare of U-shaped cross-section and which are joined together and to anangled bracket part 15a carrying connecting pins 15b.

Journalled in the corner defined by the two mutually angled rails is atelescopic, diagonal arm 43 which can be pivoted about a horizontal axis43a. The arm 43 carries at its outer end an angle piece 44 which engagesagainst a receptor 45 inserted in the holder, said arm being eithersprung and/or provided with manual locking means.

Although not shown, the arm 43 incorporates a sensor, e.g. apotentiometer or pulse emitter, which senses the prevailing length D ofthe arm.

Also arranged at the end of the arm is a further sensor (not shown)which senses the angle v defined by the arm with the horizontal.Knowledge of the arm length and the angle v is sufficient fordetermining the format of a four-cornered receptor inserted in theholder. The height of the receptor is therewith the arm length x sine vand the side of the cassette will have a length equal to the arm lengthx cosine v.

This facility for measuring the format of the receptor, necessary forobtaining automatic collimation, can also be used for image centeringpurposes, by guiding the beam source 6 for movement in the X and Zdirections with the aid of an appropriate servomechanism.

The angle pieces 41, 42, 44 are provided with two or more electricswitches (not shown) e.g. microswitches, which are activated by acorrectly positioned image receptor 45.

These switches are connected in series with an exposure switch (notshown) which is effective in blocking an exposure if the image isincorrectly centered. This will avoid subjecting the patient tounnecessary radiation dosages.

The bracket part 15a also includes a further pivot axle 46 which enablesthe universal holder 40 to be pivoted to a horizontal position, shown inbroken lines in FIG. 14. Further electric switches (not shown) indicateto the operating system whether the receptor holder has a vertical or ahorizontal position and prevents exposure when the receptor holderoccupies an intermediate position. In many cases of simple X-rayphotography, for example photographing a hand or an arm it is sufficientfor the patient to position the part of the body to be photographed on areceptor, and then to simply take a photograph. In the case of auniversal holder of the kind illustrated in FIGS. 14 and 15, thisprocedure is facilitated when the holder can be swung to a horizontalposition, in the manner indicated, so that the exposure can be made withthe beam or radiation source in a vertical position.

In many instances it is desirable to subject the patient to the leastpossible movement, particularly if the patient is badly injured orunconscious. In this regard, the present invention provides thepossibility of taking X-ray photographs of a patient positioned on,e.g., a wheeled stretcher, without needing to move the patient from thestretcher. This can be achieved by ensuring that the patient supporttable 1b can be removed, wherewith the receptor unit 7 (of FIG. 1) inthe form of a carriage which can be displaced linearly in theX-direction and Y-direction and which is movable in its frame or standis exposed. The movable stretcher can then be moved into position andthe receptor holder moved as close as possible to the underside of thestretcher. The inventive facility of synchronizing movements of thereceptor unit and the beam source is also utilized in this case.

FIGS. 16-18 illustrate the principle construction of the system ofapparatus described, the illustrated system, however, being modified tosome extent in relation to the aforedescribed embodiments.

It should be noted that the patient support table, the table top ofwhich has been removed so as to leave the table stand 1', extends atright angles to the wall along which the tower structure 2 can be moved.As before mentioned, the reference to movement in the "X-direction"still implies movement which is parallel with the longitudinal axis ofthe table, which thus means that the X and Y axes have changed places.Consequently, when moving in the horizontal plane the tower structure 2moves in the Y-direction in FIG. 16.

The arm 5 projecting outwardly from the tower structure 2 and carryingthe beam or radiation source 6 is firmly connected to the tower 2 and isthus movable in the Y-direction together with said tower. The beamsource 6 is carried by a telescopic arm 12', such that the beam sourcecan move in the Z-direction. The arm 12' is also movable in theX-direction along the arm 5. As with the aforedescribed embodiments, thebeam source can also be pivoted about a horizontal axis.

The table stand 1' is complemented by a mobile table unit 51 having awheeled frame 51a and a table top 51b. In this case, the mobile unit 51has the form of a wheeled stretcher.

The stand 1' comprises stand parts 1'a having a telescopic arrangement1'c, 1'd which carries an end support 1'f on which there is provided asupported surface 1'e for supporting the table top 51b. The end support1'f is joined with elongated guides 1'h in which the receptor unit 7 ismounted. The stand 1' also includes transverse guides 1'j for guidingmovement of the receptor unit in the Y-direction. The wheels of the unit51 are guided in floor guides 1'g.

The support surfaces 1'e arranged on the end supports 1'f and supportingthe table top 51b of the mobile unit 51 are inclined so that when themobile unit 51 is moved in above the stand 1', wherewith a guide inrespective surfaces 1'f ensures that the mobile unit takes its correctposition, the wheels of the unit are lifted slightly away from thefloor. When the mobile unit is moved in over the stand, the unit andstand are connected together automatically, with the aid of mutuallyco-acting locking means 53, 54 which "click" into one another. Thetelescopic function of the mobile unit is disengaged when coupling themobile unit with the stand 1', so that the table top 51b will followmovements of the stand 1' in the Z-direction, through the agency of itstelescopic arrangement 1'c, 1'd.

As before mentioned, a receptor unit 7 can be moved along the stand 1',and the application of a secondary receptor holder 15 to said receptorunit results in movement of the beam source 6 in the Z-direction anddisplacement of the tower stand and the beam source in the Y-directionand optionally the X-direction, together with rotation of the beamsource about its horizontal axis to a basic setting for a horizontal raypath, as with the FIG. 1 embodiment.

The secondary receptor holder 15 of this embodiment includes a pivotedarm 8', which enables the receptor holder 15 to be dropped to a parkingposition. As illustrated in FIG. 17, the receptor holder 15 can be swungup to an active position, in which the receptor holder is applied.Additionally hereto, an operating device on a panel 55 is activated foractivation of the receptor.

In the case of the FIG. 17 embodiment, the secondary receptor holder 15is provided with telescopic arms 15d. This enables movement in theY-direction to be utilized from the edge of the table to its centerline. Application of the receptor holder from the other directionenables the whole of the patient area on the table top to be coveredfrom two directions.

It will be seen from this that the embodiment illustrated in FIGS. 16-18have a number of additional characteristic features. Thus, although theembodiment according to FIGS. 16-18 has a tertiary receptor holder 9similar to the embodiment of FIG. 1, the receptor holder of the FIGS.16-18 embodiment is not connected to the arm 5. Instead, the receptorholder 9 is carried in the frame 2 and balanced by a counterweight (notshown). When the receptor holder 9 is activated, e.g. from the operationpanel 55, the beam source 6 will move to a basic setting for horizontalbeam path at a predetermined SID.

Activation of the receptor holder 9 through a handle 9b will result incorresponding automatic movement of the telescopic arrangement 12' withthe parts 12'a, 12'b, so that the beam source 6 will always take anaccurately centered position.

As will be seen from FIG. 16, the beam source 6 is also joined to oneend of an approximately Z-shaped arm 57 which carries a fourth receptorholder 58 at its other end. The arm 57 is pivotal about the samegeometric axis as the beam source 6 and can be set to various rotationalpositions.

FIG. 18 illustrates an application in which the stretcher carriage 51has an upwardly pivotable end part 51c. The Figure illustrates how anX-ray photograph can be taken, for instance, of the skull of a patientwith the aid of the fourth receptor holder 58, when the stretchercarriage is in a free position, i.e. not connected to the stand 1'. Thisenables the best exposure angle to be chosen in relation to the patient(not shown). With regard to the alternative embodiment illustrated inFIGS. 16-18, the beam source 6 may be swung about its horizontal axiswith the aid of a setting motor (cf FIG. 17) arranged on the angledshelf 13' connected to the lower part 12'b of the telescopic arm 12',and can be swung about a vertical axis with the aid of a further motor(not visible in FIG. 17). When the mobile unit 51 is disengaged from thestand 1', the telescopic arrangement on the tower structure will beactivated such that the table top 51b will remain at the set height. Thepossibility of changing the height of the stand 1' is blocked at thesame time.

An alternative embodiment is also conceivable in which the table top 51bis left on the stand 1' and the actual wheeled frame is removed, forinstance to provide the stand with another table top 51.

FIG. 19 illustrates a further embodiment in which the beam source 6 iscarried by a ceiling-mounted frame structure 2' via a telescopic armarrangement 12'. The ceiling is referenced 65 and a carriage associatedwith the frame 2' and capable of moving in the X-direction andY-direction is referenced 2'a. The carriage supports the telescopic armarrangement 12', said telescopic arm including parts 12'a and 12'b. Thebeam source 6 can be mounted on the part 12'b of said telescopic arm bymeans of an arrangement corresponding to that illustrated in FIGS.16-18. The beam source can be swung about a horizontal axis with the aidof a motor 60. In the case of this embodiment, the receptor unit 7carried by the table 1 has the form of a stationarily mounted holder 70for a secondary receptor. In this case, the arrangement is such that thefixed arrangement of the secondary image receptor will not have anysubstantial deleterious influence on the use of the receptor unit fortaking photographs with a vertical beam or ray path and will notunnecessarily impede the work of the operator in, for instance, carryingout adjustments.

The beam source 6 also co-acts with a tertiary receptor holder 71fixedly arranged in the X-direction and Y-direction. The holder 71 ispreferably located adjacent a wall in the room in which the X-ray systemis located, in a manner so as not to obstruct as far as possible theremaining activity carried out in the room.

The holder 71 can only be moved in the vertical direction and isprimarily intended for taking lung X-ray photographs, although it canalso be used for other purposes.

In the case of this embodiment, the operating panel 55 of the receptorunit 7 has approximately the same length as the actual unit (i.e.extension in the X-direction).

The operating panel 55 includes a plurality of press buttons 55a whichare provided with signs indicating the various positions of the beamsource 6. The operating panel also includes buttons for activating thevarious receptors present and therewith enabling positional adjustmentsto be made to the beam source.

The operating panel also conveniently includes separate buttons forzero-setting at selected receptor unit positions, so that differentdesired and also registrable settings of the receptor unit from such azero-setting can be undertaken with corresponding movement of the beamsource subsequent to activating the beam source drive means.

This embodiment also suitably includes a so-called touch-handle 8located in the proximity of the operating panel 55 for setting movementsof the receptor unit.

FIG. 20 illustrates the improved possibilities afforded by an inventivesystem when carrying out X-ray tomography. The layer height can bechanged by varying the distance travelled by the receptor relative tofocus.

An inventive system is able to engender two mutually unconstrainedmovements, viz. movement of the beam or radiation source 6 and movementof the receptor holder 7 with its receptor 6a. These movements are notmechanically coupled. Consequently, no separate function is required forchanging the layer height, since this possibility is found incorporatedin the system. The system thus enables simple variation of the layerheight.

Furthermore, the system enables the film speed to be varied during theactual exposure, for the purpose of obtaining angled layers. In thiscase, a progressive increase in speed will provide the same effect as anincrease in layer height during an exposure.

A conventional image amplifier (not shown) for irradiation of thepatient can also be mounted on the inventive receptor unit.

The type of grid used together with a receptor in a given case can beentered into the operating panel, wherewith the system will detect thecollimation undertaken. The values inserted into the operating panel maysuitably be shown on a display device. A given type of grid, or raste,has a pre-determined number of lines/centimeter and "ratio", i.e. theratio of grid height/lamella spacing. When inserting the line number and"ratio" tabled values of SID-tolerance are found available for eachgrid, e.g. in softwear form. The SID-tolerance may also be changed forincreased collimation. It is possible in this way to ensure that thegrid concerned will be located within the SID-range permitted by thegrid.

In summary, the exposure can be controlled automatically and the highestdegree of collimation possible can be achieved. Furthermore, it ispossible to deviate from the focus-distance concerned in differentindividual cases, which contributes to optimum image quality, which, inturn, forms a basis for a correct diagnosis and reduces the risk of thepatient being subject to unnecessary radiation dosages.

It is also possible to replace an X-ray cassette with some other form ofradiation receptor. For example, it is possible to use image plates,which normally have the same external measurements as X-ray filmcassettes and the ability of which to absorb radiation corresponding toan X-ray image is used for electronic image storage.

INDUSTRIAL APPLICATION

As will be understood from the aforegoing, the invention provides theimportant advantage of enabling the operator to work at a comfortableheight and ensures that the operator need only handle a small mass whenadjusting the settings of the receptor unit in the X-direction andY-direction. The work carried out by the operator can be facilitatedstill further by utilizing the movements performed by the holder whenchanging a receptor to automatically decenter and center the receptor inboth the x-direction and the Y-direction, the decentering movementreleasing the receptor for replacement with another receptor.

The possibility of removing the patient support table and moving awheeled stretcher over the receptor unit, which is located in anunderlying frame element, is another particularly important advantageafforded by the invention. This obviates the need to manipulate aseriously injured patient. The aforedescribed simple receptor-unitadjustment possibilities remain and the beam or radiation source ispositioned automatically subsequent to placing the primary receptorholder on the receptor unit located beneath the table, or subsequent toplacing a secondary receptor holder on said unit. All X-ray equipmentknow hitherto assumes that the patient needs to be manipulated, at leastwhen photographing certain parts of the body or body organs. The basicconcept of the invention obviated substantially all such need tomanipulate or re-arrange the patient.

The advantages afforded by the invention are contingent on receptor andbeam-source co-action incorporated in the system. The operator decidesin each individual case which receptor shall be used, and takes thenecessary steps for applying or activating this receptor, e.g. bypressing corresponding buttons on the operating panel, whereafter thebeam source is moved automatically to a basic setting positioncorresponding thereto. A desired receptor can be applied or fitted,e.g., by swinging the receptor from a lowered position (parkingposition) on one side of the table top, or beneath the table top.

It is possible by pressing a separate button on the operating panel,e.g. in the case of an emergency, to cause the equipment applied to moverapidly and effectively to an unimpeding position, to a parkingposition, so that the necessary measures can be taken immediatelywithout obstruction by the X-ray equipment and without the patient beinginjured in any way.

I claim:
 1. A method of X-ray photography in which there is used a beamor radiation source which is carried for movement in the X, Y and Zdirections and can be rotated about a horizontal axis, a patient supporttable and a receptor unit which is carried beneath the table formovement in the X- and the Y-directions and which when displacedlinearly results in automatic movement of said source, characterized inthat activation of a secondary receptor associated with the receptorunit and extending in the vertical plane results in automatic movementof said source to a basic setting for a horizontal, centered beam pathon the secondary receptor.
 2. A method according to claim 1,characterized in that activation of the receptor unit located beneaththe patient support table causes said source to return to a basicsetting-for vertical beam path onto the receptor unit.
 3. A methodaccording to claim 1, characterized in that the secondary receptor isplaced on a holder which is associated with the primary receptor unitand movable together therewith, prior to activating the secondaryreceptor.
 4. A method according to claim 1, characterized in thatadjustment of said source to a setting for an angled beam path resultsin corresponding displacement of one of said receptors in theX-direction and/or the Y-direction for constant source-image-distance.5. A system for X-ray photography comprisinga) a patient support table(1; 1', 51) which includes a receptor unit (7; 40) arranged forhorizontal movement beneath the table; b) a beam or radiation source (6)which is arranged for movement in the X, Y and Z direction and capableof being rotated about a horizontal axis; and c) drive means foreffecting linear displacement and rotational movement of said source(6), said drive means causing movement of said source subsequent tomovement of the receptor unit (7; 40), characterized in that d) thereceptor unit (7) is configured to also accomodate a holder (15, 15';40; 70) intended for receiving a vertically extending secondary receptorfor a horizontal beam path, and e) the system includes operating meansso constructed that activation of the secondary receptor will cause animpulse to be sent to the drive means so that said source (6) isadjusted to a basic setting for horizontal centered beam path onto thesecondary receptor.
 6. A system according to claim 5, characterized inthat the receptor unit (7) is configured to receive different kinds ofsecondary receptor holders (15; 15'; 15"; 40; 70).
 7. A system accordingto claim 6, characterized in that said source (6) is carried by a framestructure (5) which also carries a tertiary receptor holder (9); and inthat said source (6) is intended to take a third basic position relativeto said tertiary receptor holder subsequent to activation of anoperating device.
 8. A system according to claim 7, characterized inthat one end of the patient support table has arranged thereon a seatunit (18), which can be moved in the Y-direction, and a secondaryreceptor (15') corresponding to said seat unit and capable of beingplaced in said receptor unit.
 9. A system according to claim 5,characterized in that the patent support table comprises a stand (1'),which carries the receptor (7), and a mobile unit (51) which comprises atable top (51b) and which can be moved in over the stand (1'), saidmobile unit being detachably connectable to the stand and subsequent tobeing coupled thereto accompanies the setting movements of the stand inthe Z-direction.
 10. A system according to claim 9, characterized inthat the system includes a frame structure and said source (6) iscarried by a telescopic arrangement (12') connected to the framestructure (2,5; 2') of the system.
 11. A system according to claim 10,characterized in that the receptor unit (7) is provided adjacent holdermeans (8: 8a; 8') for the secondary receptor with an operating panel(55) provided with means for activating the drive means.
 12. A systemaccording to claim 11, characterized in that the secondary receptorholder (40) comprises two rails (41,42) of U-shaped cross-section whichforms a corner angle of 90° with one another, and a telescopic arm (43)which is pivotable about an axle located in said corner, said telescopicarm having provided at one end thereof engagement means (44) forengagement with a receptor (45) placed in the holder, the prevailinglength of the arm and the prevailing angle defined by said arm with thehorizontal providing a measurement for the dimensions of the cassetteinserted in the holder.
 13. A system according to claim 12,characterized in that the holder (40) is arranged on a bracket structure(15a) provided with connecting pins (15b) and capable of being pivotedabout an axle (46) to a horizontal position.
 14. A system according toclaim 9, characterized in that the top (1b) of the patient support table(1) can be removed to permit a mobile unit, (51) to be moved in over thestand (1') fitted with the receptor holder (7).
 15. A system accordingto claim 14, characterized in that said source (6) can be rotated abouta vertical axis and is activated for such rotary movement by a motor.